For the past decade or more, I have been thinking about the love, science, and theology interface. The questions about how these three major domains of inquiry might relate to one another are complex, and these questions require complex but understandable answers.

One of the central issues in this kind of interdisciplinary love research is how one defines love itself. Many go about assuming they know what love is. But most people—including scholars—have not done the careful work of composing a love definition.

To some people, the idea of defining is sheer foolishness. Love escapes any defining, they say. Pressing them to identify how they know which actions are loving and which are not, however, reveals quickly that they do adopt some definition of love. These adopted definitions are often tacit, intuitive, or largely unconscious.

Part of the love scholar’s task is to make explicit and conceptually coherent love assumptions that may currently remain implicit and incoherent. In my book Defining Love: A Philosophical, Scientific, and Theological Engagement, I explore various facets of love in various disciplines. I do the work of making the implicit explicit and the incoherent coherent.

Perhaps the most important contribution of the book is my proposed love definition. I define love in this way:

To love is to act intentionally, in sympathetic/empathetic response to others (including God), to promote overall well-being.

I explore each phrase of my proposed definition in the book. When it comes down to the basics, love has three essential elements:

Defining Love begins with philosophy and asks various questions about these three elements. Along the way, the book addresses forms of love such as agape, eros, and philia.

The heart of the book explores recent research and theory in science. I focus on the social sciences in one chapter, the biological sciences in another, and cosmology in a third.

I have had the great privilege of having access to some of the most influential scientists of our time. The chapters on science and love in the book draw from their work, some of which I heard them present personally, others which they detail in their published works.

Readers likely will be surprised at the vast amount of research and theory pertaining to love, altruism, well-being, prosocial behavior, agape, benevolence, and related issues in science. Reviewers and readers often report being unaware of so much interesting research being done on these subjects.

Defining Love concludes with a chapter exploring God’s love. It quickly surveys the general approaches to how science and theology might most effectively relate. Rejected are the views that say or imply that theology always trumps science or science always trumps theology.

One of the more creative proposals in this final chapter emerges from the theological issue most worrisome to those who believe God loves perfectly: the problem of evil. I call my response to the problem of evil “essential kenosis.”

Essential kenosis says God acts as a loving causal agent in every agent or event. But God never entirely determines anyone or anything. To put it another way, God never totally controls others. Because of this love-grounded power, God should not be thought the cause of evil nor be thought culpable of failing to prevent it.

Essential kenosis does say, however, that God’s love varies. God’s persuasive influence oscillates as creatures respond appropriately or inappropriately. And God expresses diverse forms of love. Divine love is not an amorphous “steady state” or “blind force,” because God is personal.

Some reviewers of Defining Love have praised the general structure and substance of the book. But many theologically informed readers find the final chapter too brief.

Anticipating this, I published simultaneous with Defining Love a thoroughly theological exploration of love called The Nature of Love. In it, I wrestle with classic love theologians like Augustine and Anders Nygren. And I propose a series of ideas pertaining to essential kenosis that should satisfy readers of Defining Love who had hoped for more theological reflection.

My hope is that Defining Love becomes a tool for both academics and laity as they wrestle with love’s meaning and expression in the world. The research will likely surprise many. And I trust that my own proposals will prove fruitful in the ongoing work to gain a better understanding of God and creation.

Thomas Jay Oord (PhD, Claremont Graduate University) is professor of theology and philosophy at Northwest Nazarene University in Nampa, Idaho, and is ordained in the Church of the Nazarene. He is the author of Science of Love and the editor of The Altruism Reader.